A blog about some of the Antarctica Weddell seal population study field research work and outreach efforts during the Weddell seal pupping season in the Erebus Bay region of Antarctica's Ross Sea. Weddell seal images and recordings obtained under NMFS Permit Nos. 1032-1917, 17236, and 21158. More information at http://WeddellSealScience.com

Weddell seal pups are born on top of the sea ice in Antarctica, and spend a lot of time with their moms in their first 45 days or so. They’re nursing, getting fat on their moms' milk, and learning how to swim with their moms' help. And they’re probably learning how Weddell seals behave by watching their moms and other seals interact around the colony.

But when the pups are around 50 days old, their moms leave them on their own to survive with what they’ve learned and the weight they’ve gained from all that nursing. The fact is that only around 20% of the female pups born in a cohort—born in the study area pupping colonies during the same pupping season—will survive to around 7 or 8 years old, which is when most females start having pups. During that time they will grow in size from a small adorable pup to an animal the size of a horse, and must be healthy enough to gain enough weight to be able to produce a pup and do the really big job of caring for that pup (like giving up half of their body weight during the pup-nursing period).

What makes the difference between surviving, growing, and being healthy enough to have a pup themselves—or dying before they’re old enough to do that? It turns out that who a pup's mom is can make an important difference in whether that pup survives to reproduce, or doesn't.

In one way, all Weddell moms are exceptional. They are among the relatively small group of females that live long enough to return to the colonies and reproduce. But within that small group of Weddell females that return to give birth, there are a lot of differences among those moms; and those differences can have an important influence on whether their pups survive to return, and have pups of their own. What scientists working over the years on this National Science Foundation funded Weddell seal population study have learned has come about as the result of a nearly 5 decade-long population study and its extensive multi-generation database.

The ways these project scientists have learned about what differences in Weddell seal moms can mean to their pups, is the result of decades of tagging nearly every new seal pup born in the study area to know how many pups are born each year, who their moms are, how much some of the pups weigh at birth, at the mid-nursing period, and then at weaning, as well as how much some of the moms weigh when they come in and give birth. The scientists are very interested in learning more about how much weight the moms lose during the nursing period.

Over the past 6 years researchers have also been using small temperature/time recording tags on some female pups to measure how much time those pups spend in the water, where they can develop swimming skills, learn to avoid larger animals, dive and search for food, and other important skills for life on their own.

For female pups born 10 years ago or more, the researchers will be able to assess which pups have survived to come back and produce pups of their own. This can be done because for this special population it is possible to tag and record every mom-pup pair every pupping season. The individual tags on the animals let the researchers know who’s who, how old they are, who their mothers are, and how many pups they’ve had to date. For female seals that received small temperature/time recording tags when they were pups (the small red tag in the photo above), the scientists will also know how much time those seals spent in the water when they were pups.

Using these data, the researchers apply powerful statistical methods to study what differences in moms can mean to their pups’ future survival and reproductive adulthood. Here’s some of what the scientists have learned about the ways in which moms differ, how they matter to their pups, and what makes a good mom.

First, a pup would want a mom that was born into a large birth cohort herself as such females typically experienced good environmental conditions early in life, making them prone to success later in life. Then, a pup would want a mom who came into the breeding colonies in the years before her first pup birth to possibly learn more seal behavioral skills from moms already having pups.

A pup would want a mom who, the year before that pup was born, had come into the colonies to select a good male to mate with, while she synchronized her breeding cycle with the other females. This way the pup would be born when the rest of the pups in that cohort were being born the next pupping season, which can be important for many reasons.

A pup would want its mom to have good marine conditions with plenty of food resources after she mated so that her pregnancy would begin. Weddell seal females are what are known as “delayed implanters”—the fertilized egg doesn’t implant in the mom’s womb until a month or longer after she mates. She somehow physiologically “chooses” whether the egg will implant to allow the embryo to begin to develop. Studies suggest that the availability of marine resources—food— and the female’s resulting physiological condition affect whether or not the fertilized egg will implant.

A pup would want its mom to be of prime age—somewhere in her early to mid teens—as that’s when females tend to have (1) experience at raising pups, (2) their maximal body weight, and (3) no obvious signs of age-related deterioration. The Weddell seal population scientists have learned over the course of this long-term study that Weddell females give birth to their first pups at different ages. Some give birth as early as 5 years old, but most females have their first pup around 7 or 8 years old. Those females that give birth earlier in life seem to be especially good at producing pups regularly over their lifetime and are more apt to produce pups that thrive.

The average mom will have around 7 pups over a typical lifespan of 16 years or so. She would have 1 to 2 pups about every 3 years. Yet some moms live much longer—into their 20s, and even 30s. Some females never do have a pup, while some have many pups over a longer lifetime. In the study area, there was one mom who was 31 years old and had 22 pups during her lifetime!

So moms differ a lot as to when they first give birth, how long they live, and how many pups they give birth to over their lifetimes. What project scientists have learned is that your ideal mom would likely be a mom that started having pups at an early age, has had lots of experience raising pups previously, and is of prime age.

A pup would also like its mom to have skipped having a pup the previous year so that she is in great body condition with lots of stored energy in the form of more body fat the year the pup is born. After it's born, the pup would want a mother who spends lots of time with her pup nursing—transferring lots of weight to her pup throughout the nursing period.

A Weddell pup would want its mom to have lots of experience raising pups so she is good at helping her pup learn to swim when the pup is around 1 to 2 weeks old, and will do a good job raking the sea ice with her front teeth to make ice ramps that can help her pup get into and, especially, out of the water. Since raking ice can wear down a mom’s teeth over the years, a pup would want a prime age mom with good, sharp teeth.

When a Weddell pup is born, it will weigh anywhere from 40 to 70 pounds. After the roughly 35 to 45 day nursing period, it will weigh anywhere from the low 100s up to 300 pounds, or more! The project scientists have learned that how much a pup weighs when it's weaned is related to characteristics of the pup's mom.

One difference among Weddell moms affecting how much weight their pups gain is the age of the mom. Pups of younger moms start out lighter and tend to gain less weight. Pups of the oldest moms also start out lighter, but have mothers near the end of their lives that invest heavily in their pups and wean their pups at similar weights to pups from prime-age moms. So, the scientists hypothesize that a pup should be better off with a mom of prime age or older and hope to test that idea in the coming years.

While with many large long-lived mammal species, scientists have learned that weaning heavier is better for offspring survival, this may be more complicated with Weddell seal pups. For Weddell pups the nursing period—when pups are closely interacting with their moms and learning new skills like how to swim and get in and out of the water, and other behavioral skills—is longer than in most other seals.

Project scientists are now studying whether there is some kind of tradeoff between how much weight a pup gains during the nursing period versus the pup swimming a lot and possibly learning more survival skills from its mom underwater, but gaining less weight due to all that activity. The scientists are using small temperature/time recording tags on some of the pups to measure how long and how often they are in the water, and weighing those pups to learn how much weight they gain, so that the researchers can later learn which pups went on to survive to have pups themselves, "recruit".

One of the most interesting aspects of differences among moms that the project scientists have recently discovered is that after all the different measurable characteristics of moms are accounted for, some moms are just better at having and raising pups than others, and this is a fixed characteristic of those moms. This fixed characteristic of just being better at having pups remains the case whether it is good year for pupping or a far more challenging year, such as when a massive iceberg blocked access to the pupping areas in the past decade.

Using all of these valuable data collected over the decades by researchers, coupled with newer, more powerful approaches to statistical modeling, project scientists are able to learn more about these characteristics of Weddell moms that influence how likely their pups are to survive and grow up to be moms themselves. And, we’ll gain an even better understanding of how maternal investment in pups relates to differences in Weddell moms and changes in the environment.

One thing is certain from this long-term population study to date: if you’re a Weddell seal pup, who your mom is can make important differences in whether you will be among the exceptional 20% of female pups to survive and return to the study area pupping colonies to have pups of your own.

28 October 2017

With the pace of seal pup births increasing, the Antarctica field team based at the remote sea ice camp at Big Razorback Island is making continuous sweeps through the numerous Weddell seal pupping colonies to assess all the new pups and moms. The remote sea ice camp should get wireless internet connection soon, and we'll get more real-time updates from the field team when that happens. Wireless internet connection at the sea ice camp is quite amazing. Here's a video from a previous season about how the wireless connection is established, and relayed via satellite:

While we await this season's remote wireless internet connection, and with it direct contact with the field team on the ice, here's an update of what the team is doing at this point in the pupping season.

A day or so after a new pup is born, it is added to the nearly 50 year database of multi-generations of Weddell seals in the Erebus Bay study area. The pup's condition is determined and recorded, as is the location of its birth, and the identity of its mother. The pup is tagged with a very small identity tag, and weighed if its mother is a "known mom"--a Weddell female whose own birth and data are recorded in the longterm database. The pups will be re-weighed at two more points during its approximately 35 to 40 day nursing period. Genetic samples will be obtained, and some pups born to known moms will receive a small temperature/duration recording tag that will be removed at the final pup weighing near weaning time.

This small temp tag will record the surrounding temperature every 6 minutes. Because the air temperature in Antarctica is highly variable, but the water beneath the ice remains a constant 29 degrees Fahrenheit, researchers will be able to determine when the pups were in the water, and for approximately how long. Known moms will also have their mass (weight) assessed. The field team is using a less intrusive approach to assessing a seal's mass using a photogrammetric method that involves photographing the seals and using 3D computer modeling analysis to obtain their mass. At 5 to 8 points in the pupping season, the field team will do a survey of all the Weddell seals in the study area, at all the pupping colonies. This helps ensure accuracy of the season's seal census. Here is a map of the study area showing the main pupping colonies and the location of the remote sea ice field camp at Big Razorback Island.

As we await further contact from the field team, here's our latest short stereoscopic 3D video science story which received a great reception at the recent National Stereoscopic Association/International Stereoscopic Union 3D-Con Stereo Theater premiere screening:

20 October 2017

Weddell seal pupping season is underway, and pregnant Weddell seal moms are swimming under the sea ice in Erebus Bay to access safe pupping colony areas on top of the ice to give birth. With the 2017 Antarctica Field Team on the ice now, including project lead scientist Jay Rotella and author/imager Jeremy Schmidt, the entire crew is working hard from the remote sea ice camp to quickly assess and record every Weddell pup born in the Erebus Bay study area pupping colonies. Here's a short video of a Weddell mom giving birth to her new pup. This video from a previous season was recorded in high definition by Mary Lynn Price, thanks to the sharp eyes of field team co-crew leader Jesse DeVoe who first noticed the Weddell mom-to-be behaving in a way that looked like she might be ready to pup. Thank you, Jesse! More on the population study work of the field team and more baby seals in our upcoming posts...

The giant transport jet landed on the sea ice shelf outside McMurdo Station, and the team was driven to McMurdo on the famous "Ivan the Terra Bus".

Here's a video from a previous season showing the C-17 boarding process in Christchurch, New Zealand, a trip up to the cool C-17 cockpit, the subsequent deplaning on the Sea Ice Shelf, and the drive to McMurdo Station on Ivan the Terra Bus...

The team is now finishing up training at McMurdo, and will head out to the remote sea ice camp at Big Razorback Island to join the 1st wave of the field team, Kaitlin Macdonald, Shane Petch, and Thomas Sutton, that helped get the remote sea ice camp in order after the camp pull. Here's a video of the camp pull from a previous season with imaging by Jessica Farrer...

11 October 2017

The 2nd wave of Weddell seal population study field team members, Co-crew leader Jesse DeVoe, Alissa Anderson, and Aubrey Power, have been waiting these past few days for the sea ice runway conditions to improve outside McMurdo Station before being flown from Christchurch, NZ to the Ice to re-unite with colleagues Kaitlin Macdonald, Shane Petch and Thomas Sutton already there.

So we are very excited to take this opportunity to introduce two wonderful field blogs being updated by a couple of our team members throughout the Weddell pupping season!

Jesse DeVoe first deployed to Antarctica as part of the Weddell seal field team from 2010 through 2012. He did 3 pupping season deployments with the Weddell population study, maintaining his fantastic blog throughout. Jesse would go on to receive his MS from Montana State University-Bozeman. He returns to the Ice this season as a co-crew leader on the project. Jesse is a wonderful photographer, writer, videographer, viral video producer, and a great up-and-coming ecologist. This season he will be doing a lot of social media posting on the project, and working with some interesting immersive video approaches. All this in addition to his primary work of helping to carry out the scientific field goals of the Weddell population study this pupping season!

The second blog is brand new by 2017 Antarctica Field Team member Aubrey Power, and is named The Wandering Weddell. This is Aubrey's 1st deployment to Antarctica, and she will be sharing her experiences throughout the pupping season. More info on Aubrey is available on her very cool blog.

We will await word from the field team about the flight to Antarctica, and the 'camp pull' that is happening on the ice. The camp pull is when all the huts that make up the study's remote sea ice camp will be pulled by ice tractor to the location on the sea ice of this season's remote camp.

In the meantime, please enjoy these 2 wonderful field blogs to get a better sense of what field team members are doing and experiencing!

10 October 2017

The advance Weddell seal population study sea ice team is finishing up some of the most fundamental work of the Antarctica field season: flagging safe routes over the sea ice to access the various Weddell seal pupping colonies. Flagging safe sea ice routes involves determining where cracks in the sea ice exist, and planning safe routes to avoid these cracks. Then flags are placed close enough together in set intervals to indicate where it's safe to travel. Crack size is determined by probing, digging, and drilling using either a power hand drill or a manual hand drill. In these photos below from field team co-crew leader and Montana State University MS student Kaitlin Macdonald, Shane is seen using the manual hand drill to flag a crack near Turtle Rock.

In the photo above Thomas and Shane are flagging a route from Turtle Rock to Big Razorback remote sea ice camp. They are using a Pisten Bully to travel along the sea ice route and set flags. Below, the flag-laden Pisten Bully with Shane and Thomas drilling ice and setting flags.

In addition to flagging safe routes to the Weddell pupping colonies, the field team also marks crack areas to stay away from. The photo below shows two black flags marking a crack radiating from Turtle Rock.

Here's a video from a previous season showing field team flagging from snowmobiles...

05 October 2017

The 2017 Weddell study field team on the ice is now hard at work getting everything together for the Weddell pupping season in Erebus Bay, Antarctica. Equipment needs to be set up and tested, safe sea ice routes need to be established and flagged to the various Weddell pupping colonies in the Erebus Bay Study Area, and the wooden fish huts need to be prepped and stocked for the "camp pull" coming up. This is when the remote sea ice camp huts, from which the Weddell seal field team will live and work during the entire pupping season, will be pulled out to the site of this season's remote sea ice field camp.

In the photo above by MS student and co-crew leader Kaitlin Macdonald, 2017 field team members Shane Petch and Thomas Sutton work in the McMurdo Crary Science Building to sort and assemble the small tags that will be used this season.

In this photo by Thomas Sutton, Shane Petch is preparing the Weddell population project's lab room in the Crary Science Building at McMurdo Station, Antarctica. The lab has gorgeous views out the windows toward the Royal Society Mountains and sea ice transition where the sea ice meets the ice shelf.

Above, Shane and Thomas stand before the heroic era Scott Hut at Hut Point. There are three wooden huts from the heroic era of Antarctica exploration and science in the general area where the Weddell seal population study's wooden huts will be placed on the sea ice for the Weddell pupping season. Two of the heroic era huts were built by Robert Falcon Scott and his men. One of the historic huts is the Sir Ernest Shackleton Nimrod Expedition hut. History is everywhere here! You can check out one of our prior blog posts on the heroic era huts in the Erebus Bay area, or read more about the Weddell seal population study's nearly 50 year history in the Project History section of our main web portal, WeddellSealScience.com.

In Shane's photo above, Thomas works to adjust and calibrate the camera positioning for the upcoming photogrammetric imaging of the seals in the field to accurately assess their mass (weight) in a non-intrusive technique involving photos and 3D computer modeling and interpolation.

Coming up, we'll get a closer view of the sea ice route flagging teamwork, as safe sea ice routes to the numerous Weddell pupping colonies are established by the team. Please stay tuned!